TECHNICAL FIELD
[0001] The present invention relates to a method of treating or preventing osteoporosis.
Specifically, the present invention relates to a well-defined regimen for the intermittent
dosing, in a limited amount for a limited time , of certain polyphosphonate compounds.
The present invention further relates to a kit to be used by patients for effectively
implementing the method of treatment of the present invention.
BACKGROUND OF THE INVENTION
[0002] Osteoporosis is the most common form of metabolic bone disease. Although it may occur
secondary to a number of underlying diseases, 90% of all cases appear to be idiopathic.
Postmenopausal women are particularly at risk to idiopathic osteoporosis ("postmenopausal
osteoporosis"). Another high risk group for Idiopathic osteoporosis are the elderly
of either sex ("senile osteoporosis").
[0003] in the various forms of osteoporosis, bone fractures, which are the result of bone
loss that has reached the point of mechanical failure, frequently occur. Postmenopausal
osteoporosis is characterized by fractures of the wrist and spine. Femoral fractures
seem to be the dominant feature of senile osteoporosis.
[0004] The mechanism by which bone is lost in osteoporotics is believed to involve an imbalance
in the process by which the skeleton renews itself. This process has been termed bone
remodeling. It occurs in a series of discrete pockets of activity. These pockets appear
spontaneously within the bone matrix on a given bone surface as a site of bone resorption.
Osteoclasts (bone dissolving or resorbing cells) are responsible for the resorption
of a portion of bone of generally constant dimension. This resorption process is followed
by the appearance of osteoblasts (bone forming cells) which then refill with new bone
the cavity left by the osteoclasts.
[0005] lr, a healthy adult subject, the rate at which osteoclasts and osteoblasts are formed
is such that bone formation and bone resorption are in balance. However, in osteoporotics
an imbalance in the bone remodeling process develops which results in bone being lost
at a rate faster than it is being made. Although this imbalance occurs to some extent
in most individuals as they age, it is much more severe and occurs at a younger age
in osteoporotics.
[0006] There have been many attempts to treat osteoporosis with a variety of pharmacologic
agents with the goal being to either slow further bone loss or, more desirably, to
produce a net gain in bone mass. It appears as though there are agents available,
such as estrogen, which will slow further bone loss in osteoporotics, but agents or
methods of treatment which will result in the replacement of bone which has already
been lost have been very elusive.
[0007] The ability of polyphosphonates to inhibit bone loss has been well documented in
animals and man. However, these compounds have, thus far, not proven to be particularly
useful in diseases such as osteoporosis where there is chronic loss of bone, and therefore
a perceived need for chronic treatment. The reason for this probably lies in the tight
coupling between the bone resorption and formation in the human skeleton. When one
attempts to chronically manipulate one phase of the skeletal remodeling cycle (bone
resorption or formation), a similar effect occurs in the opposing process and any
change produced is then negated. In the case of polyphosphonates, chronic inhibition
of bone resorption tends to produce chronic inhibition of bone formation. Furthermore,
long term chronic inhibition of remodeling is not desirable since it appears that
this may lead to the development of spontaneous bone fractures.
[0008] It has now been discovered that bone loss can be inhibited and bone mass can be increased
if certain polyphosphonates are given, in a limited amount, according to a specific
regimen of intermittent, rather than chronic, dosing. This regimen forms the heart
of the present invention. This treatment apparently uncouples bone resorption and
formation by selectively inhibiting the resorption phase of bone remodeling without
appreciably affect!ng the formation phase, and thus producing the net increase in
skeletal mass.
[0009] It is therefore an object of the present invention to provide a method for treating
or preventing osteoporosis which does not require prolonged administration of pharmacologic
agents, and which does not result in a significant inhibition of bone formation.
[0010] A further object of the present invention is to provide a kit to facilitate the necessary
strict compliance with the method of treatment of the present invention.
[0011] U.S. Patent 3,683,080, to Francis (issued August 8, 1972), discloses pharmaceutical
compositions containing polyphosphonate compounds. These compositions are useful for
inhibiting deposition and mobilization of calcium phosphates in animal tissue. This
patent also discloses a method for treating or preventing conditions involving pathological
calcification and hard tissue demineralization, such as osteoporosis, in animals by
utilizing the chronic dosing of these compositions.
[0012] U.S. Patent 4,230,700, to Francis (issued October 28, 1980), discloses the conjoint
administration of certain polyphosphonate compounds, in particular diphosphonates,
and vitamin D-like anti-rachitic compounds for inhibition of the anomalous mobilization
of calcium phosphate in animal tissue. See also U.S. Patent 4,330,537, to Francis
(issued May 18, 1982). The patents specify that the administration of the phosphonate
and the vitamin D-like compounds be conjoint.
[0013] Siris et al., Arthritis and Rheumatism, 23 (10), 1177-1184 (1980), discloses research
into intermittent therapy for Paget's disease involving high doses of EHDP or long
periods of treatment with EHDP.
[0014] Rasmussen et al., "Effect of Combined Therapy with Phosphonate and Calcitonin on
Bone Volume in Osteoporosis", Metabolic Bone Disease and Related Research, 2, 107,
(1980), discloses a treatment regimen consisting of continuous administration of inorganic
phosphate and intermittent administration of calcitonin.
[0015] Anderson et al., Calcified Tissue international, 36, 341-343 (1984), discloses a
sequential and intermittent method of treating osteoporosis based on the ADFR theory
of bone treatment which requires a period during which a bone activation compound,
such as inorganic phosphate, is administered to the patient, to be followed by a period
during which a bone resorption repressing compound, such as ethane-1-hydroxy-1,1-diphosphonic
acid, is administered, followed by a period free of medication to allow the bone to
be built up.
SUMMARY OF THE INVENTION
[0016] The present invention relates to a method of treating or preventing osteoporosis,
in humans or lower animals afflicted with or at risk to osteoporosis, utilizing a
regimen comprising two or more cycles, whereby each cycle comprises a period of from
about 1 day to about 90 days during which a bone resorption inhibiting polyphosphonate
is administered daily in a limited and effective amount, and a rest period of from
about 50 days to about 120 days during which no bone resorption inhibiting agent is
administered.
[0017] The present invention further relates to a kit for use in the above-described cyclic
regimen, said kit containing the following components: from about 1 to about 90 daily
doses, with each daily dose containing a limited and effective amount of a bone resorption
inhibiting polyphosphonate; from about 50 to about 120 daily doses of a placebo or
a nutrient supplement; and a means for having the components arranged in a way as
to facilitate compliance with the regimen.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The present invention relates to a method of treating or preventing osteoporosis,
in humans or lower animals afflicted or at risk to osteoporosis, utilizing a cyclic
regimen consisting of two or more cycles, whereby each cycle comprises: (a) a period
of from about 1 day to about 90 days during which a bone resorption inhibiting polyphosphonate
is administered daily in a limited and effective amount, preferred amount being from
about 0.25 X LED to about 4 X LED, with from about 0.25 X LED to about 2.5 X LED most
preferred; and (b) a rest period of from about 50 days to about 120 days, preferred
being from about 70 days to about 100 days, with about 84 days most preferred. This
regimen is particularly effective In preventing bone loss, and causing bone mass to
increase, in subjects afflicted with or at risk to osteoporosis.
[0019] Each cycle within the regimen may be of equal length or the cycles may vary in length.
Either the length of time during which the bone resorption polyphosphonate is administered,
and/or the length of the rest period may be varied from cycle to cycle. In addition,
the bone resorption inhibiting polyphosphonate may be the same or different from cycle
to cycle (e.g., alternating cycles using ethane-1-hydroxy-1,1-diphosphonate one cycle
and dichloromethane diphosphonate the next cycle), with preferred being the same bone
resorption inhibiting polyphosphonate being used each cycle.
[0020] Examples of the cycle times within a regimen are:
(1) 14 days of daily treatment with a bone resorption inhibiting polyphosphonate,
alternating with an 84 day rest period;
(2) 42 days of daily treatment with a bone resorption inhibiting polyphosphonate,
alternating with a 56 day rest period;
(3) 56 days of daily treatment with a bone resorption inhibiting polyphosphonate,
alternating with a 112 day rest period;
(4) 28 days of daily treatment with a bone resorption inhibiting polyphosphonate,
followed by an 84 day rest period, followed by 84 days of daily treatment with a bone
resorption inhibiting polyphosphonate, followed by an 84 day rest period, followed
by 28 days of daily treatment, followed by an 84 day rest period.
[0021] Preferred cycle times of the present invention are given in (1), above, with the
preferred bone resorption inhibiting polyphosphonate for this example being ethane-1-hydroxy-1,1-diphosphonic
acid, and its pharmaceutically-acceptable salts and esters. Also preferred is the
cycle times in (4), above, with dichioromethane diphosphonic acid, and its pharmaceutically-acceptable
salts and esters, preferred as the bone resorption inhibiting polyphosphonate for
this particular regimen.
[0022] The total treatment time (i.e., the number of cycles for treatment) for the method
of treatment of the present invention will vary from patient to patient based on sound
medical judgment and factors particular to the patient being treated such as, for
example, the extent of bone loss prior to starting treatment, the age and physical
condition of the patient, and whether the goal of the treatment is to prevent bone
loss or build bone mass. For example, if a certain percent increase in bone mass is
desired from the method of treatment of the present invention, the total treatment
time is as long as it takes to obtain this goal as determined through bone measurement.
Those skilled in the art know the factors to be considered, and can easily determine
the total treatment time based on these factors on a patient by patient basis.
[0023] By "human or lower animal afflicted with or at risk to osteoporosis" as used herein
is meant a subject diagnosed as suffering from one or more of the various forms of
osteoporosis, or a subject belonging to a group known to have a significantly higher
than average chance of developing osteoporosis, e.g., postmenopausal women, men over
age 65, and persons being treated with drugs known to cause osteoporosis as a side
effect (such as adrenocorticoids).
[0024] By "bone resorption inhibiting potyphosphonate" as used herein is meant polyphosphonate
compounds and compositions of the type disclosed in U.S. Patent 3,683,080, to Francis
(issued August 8, 1972); U.S. Patent 4,054,598, to Blum and Worms (issued October
18, 1977); U.S. Patent 4,330,537, to Francis (issued May 18, 1982); U.S. Patent Application
Serial No. 684,544, Benedict and Johnson (filed December 21, 1984); U.S. Patent Application
Serial No. 684,543, Benedict and Perkins (filed December 21, 1984); European Patent
Application 100,718, Breliere et al. (published February 15, 1984); the disclosures
of all of which are incorporated herein by reference. The term "phosphonate" Includes
the phosphonic acids, as well as their pharmaceutically-acceptable salts and esters.
Preferable polyphosphonates are geminal diphosphonates (also referred to as bis-phosphonates
or diphosphonates).
[0025] Bone resorption inhibiting polyphosphonates useful for the method of treatment of
the present invention include, but are not limited to, those having the general formula:

wherein n is an integer from 0 to about 7, with preferred n being 0, 1, or 2; R
1 is hydrogen, chloro, amino, or hydroxy, with R being hydrogen or hydroxy preferred;
X is -NH-, oxygen, or a single bond, with X being -NH- or single bond preferred; R
2 is a nitrogen-containing six-membered aromatic ring, or hydrogen; and their pharmaceutically-acceptable
salts and esters.
[0026] Specific examples of bone resorption inhibiting polyphosphonates include:
ethane-1-hydroxy-1,1-diphosphonic acid,
pentane-1-hydroxy-1,1-diphosphonic acid,
methane diphosphonic acid,
methane-dichloro-diphosphonic acid,
methane-hydroxy-diphosphonic acid,
ethane-1-amino-1,1-diphosphonic acid,
ethane-2-amino-1,1-diphosphonic acid,
propane-3-amino-1,1-diphosphonic acid,
propane-3-amino-1-hydroxy-1,1-diphosphonic acid,
propane-N,N-dimethyl-3-amino-1-hydroxy-1,1-diphosphonic acid,
propane-3,3-dimethyl-3-amino-1-hydroxy-1,1-diphosphonic acid,
phenyl-amino-methane-diphosphonic acid,
N,N-dimethyl-amino-methane-diphosphonic acid,
N-(2-hydroxyethyl)-amino-methane-diphosphonic acid,
butane-4-amino-1-hydroxy-1,1-diphosphonic acid,
pentane-5-amino-1-hydroxy-1,1-diphosphonic acid,
hexane-6-amino-1-hydroxy-1,1-diphosphonic acid,
indan-2,2-diphosphonic acid;
hexahydroindan-2,2-diphosphonic acid;
2-methylcyclobutane-1,1-diphosphonic acid;
3-chlorocyclopentane-1,1-diphosphonic acid;
cyclohexane-1,1-diphosphonic acid;
2-(2-pyridyl)-l-hydroxy-ethane-1,1-diphosphonic acid;
N-(2-(5-amino)-pyridyl)-aminomethane diphosphonic acid;
N-(2-(5-chloro)-pyridyl)-aminomethane diphosphonic acid;
N-(2-(3-picolyl))-aminomethane diphosphonic acid;
N-(2-(4-picolyl))-aminomethane diphosphonic acid;
N-(2-(5-picolyl))-aminomethane diphosphonic acid;
N-(2-(6-picolyl))-aminomethane diphosphonic acid;
N-(2-(3,4-lutidine))-aminomethane diphosphonic acid;
N-(2-pyrimidyl)-aminomethane diphosphonic acid;
N-(2-pyridyl)-2-aminoethane-1,1-diphosphonic acid;
2-(2-pyridyl)-ethane-1,1-diphosphonic acid;
2-(3-pyridyl)-ethane-1,1-diphosphonic acid;
2-(4-pyridyl)-ethane-1,1-diphosphonic acid;
2-(2-(3-picolyl))-oxaethane-1,1-diphosphonic acid; and
pharmaceutically-acceptable salts and esters thereof.
[0027] Preferred bone resorption inhibiting polyphosphonates for use in the regimen of the
present invention are:
ethane-1-hydroxy-1,1-diphosphonic acid ("EHDP");
dichloromethane diphosphonic acid ("Cl2MDP");
propane-3-amino-1-hydroxy-1,1-diphosphonic acid ("APD");
hexane-6-amino-1-hydroxy-1,1-diphosphonic acid ("AHDP");
butane-4-amino-1-hydroxy-1,1-diphosphonic acid ("ABDP");
2-(2-pyridyl)-ethane-1,1-diphosphonic acid ("pyr-EDP");
2-(2-pyridyl)-1-hydroxy-ethane-1,1-diphosphonic acid ("pyr-EHDP");
hexahydroindan-2,2-diphosphonic acid ("HIP"); and pharmaceutically-acceptable salts
and esters thereof.
[0028] By "pharmaceutically-acceptable salts and esters" as used herein is meant hydrolyzable
esters and salts of the diphosphonate compounds which have the same general pharmacological
properties as the acid form from which they are derived, and which are acceptable
from a toxicity viewpoint. Pharmaceutically-acceptabfe salts include alkali metal
(sodium and potassium), alkaline earth metal (calcium and magnesium), non-toxic heavy
metal (stannous and indium), and ammonium and low molecular weight substituted ammonium
(mono-, di- and triethanolamine) salts.
[0029] An important aspect of the present invention is the discovery that too high a dosage
of bone resorption inhibiting polyphosphonate is detrimental to bone formation when
following the intermittent dosing regimen according to the present invention. For
this reason, the method of treatment of the present invention requires that the daily
dosages of the bone resorption inhibiting polyphosphonates be given in a specific
limited and effective amount. The limited and effective amount of polyphosphonate
to be used in the present invention is a dally dosage for the bone resorption inhibiting
polyphosphonate which is based on the potency of the polyphosphonate as a bone resorption
inhibiting agent (as determined by the thyroparathyroidectomized ("TPTX") rat model)
in light of the characterization of the polyphosphonate as being EHDP-like or Ci2MDP-like
(this characterization being based on the tendency of the polyphosphonate to inhibit
bone mineralization relative to bone resorption inhibition as determined by the Schenk
model).
[0030] The limited and effective amount of polyphosphonate which is to be administered daily
according to the method of treatment of the present invention is therefore determined
by a two step process. First, the polyphosphonate must be characterized as being EHDP-like
or Cl
2MDP-like based on the polyphosphonate's tendency to inhibit bone mineralization relative
to its ability to inhibit bone resorption. This relative tendency to inhibit bone
mineralization is determined by the Schenk model described here- lnbelow, and is measured
by the difference between the lowest effective dose ("LED") of the polyphosphonate
to inhibit bone resorption (as determined by the Schenk model) and the lowest dosage
producing widening of epiphyseal growth plate (which is a measure of mineralization
inhibition). Polyphosphonates that have a difference between these two values of about
one log dose or less (i.e., the dose at which mineralization inhibition is observed
is less than or equal to about 10 times the LED for bone resorption inhibition) are
characterized as being EHDP-like, i.e., they have a strong relative tendency to inhibit
bone mineralization. Polyphosphonates that have a difference between these two values
greater than about one log dose (i.e., the dose at which mineralization inhibition
is observed is greater than about 10 times the LED for bone resorption inhibition)
are characterized as being Cl
2MDP-like, i.e., they have little relative tendency to inhibit bone mineralization.
[0031] Bone resorption inhibition LEDs and mineralization inhibition dose values for representative
polyphosphonates, determined by the Schenk model, are given in Tables II and III below.
Non-limiting examples of EHDP-like polyphosphonates are: EHDP and N-(2-pyridyl)-aminomethane
diphosphonic acid ("N-(2-pyr)AMDP"). Non-limiting examples of Cl
2MDP-like polyphosphonates are: CI
2MDP. APD, AHDP, ABDP and pyr-EDP.
[0032] The second step (for deciding the limited and effective amount of polyphosphonate
to be administered daily) is determining the daily oral dosages for the bone resorption
inhibiting polyphosphonates based on the potency of the polyphosphonate as a bone
resorption inhibiting agent. This potency is determined by means of the thyroparathyroidectomized
(TPTX) rat model described herein and expressed as the lowest effective dose (LED)
of the compound which is defined as the lowest subcutaneously given dose of polyphosphonate,
in mg P per kg body weight, which in the TPTX rat model results in an inhibition of
the PTH-induced rise in serum calcium level. Since the amount of polyphosphonate to
be administered is dependent on the bone resorption inhibition potency of the compound,
the amount to be administered is conveniently expressed as multiples of LED. Extrapolation
of the dosages for polyphosphonates from the TPTX rat model to humans is possible
based on the observation that oral dosages in humans are proportionally related to
the LEDs for polyphosphonates in the TPTX rat model.
[0033] It is necessary for the method of treatment of the present invention that the daily
oral dosage for EHDP-like polyphosphonates be in the range of from about 0.25 X LED
to about 4 X LED, with from about 0.25 X LED to about 2.5 X LED preferred. The range
for Cl
2MDP-like polyphosphonates is from about 0.25 X LED to about 10 X LED, with preferred
being from about 0.25 X LED to about 4 X LED, and from about 0.25 X LED to about 2.5
LED most preferred. Thus, by "limited and effective amount" as used herein is meant
daily oral dosages for EHDP-like polyphosphonates that fall within the range of from
about 0.25 X LED to about 4 X LED, and daily oral dosages for CI
2MDP-like polyphosphonates that fall within the range of from about 0.25 X LED to about
10 X LED. In particular, preferred is a daily oral dosage of about 1.25 X LED of DIDRONEL
(Norwich Eaton Pharmaceuticals, Norwich, NY; disodium EHDP in a dose of about 5 mg/kg/day).
Further particularly preferred is a daily oral dosage of about 8 X LED of Cl
2MDP, or Its pharmaceutically-acceptable salt or ester (about 20 mg/kg of the disodium
salt of Cl
2MDP). It is these critical dosage limitations, in combination with the cycle times
of the method of treatment of the present invention, that distinguishes the present
invention from other regimens of the art which utilized higher dosages and/or longer
cycle times (e.g., Siris et al., Arthritis and Rheumatism, 23 (10), 1177-1184 (1980)).
The LEDs for a number of polyphosphonates are collected in Table I.
[0034] Ranges for the daily administration of some polyphosphonates for subjects afflicted
with or at risk to osteoporosis are therefore: EHDP: from about 0.25 mg P/kg to about
4 mg P/kg, with from about 0.25 mg P/kg to about 2.5 mg P/kg preferred; C1
2MDP: from about 0.12 mg P/kg to about 5 mg P/kg, with from about 0.12 mg P/kg to about
2 mg P/kg preferred, and from about 0.12 mg P/kg to about 1.25 mg P/kg most preferred;
APD: from about 0.025 mg P/kg to about 1 mg P/kg, with from about 0.025 mg P/kg to
about 0.4 mg P/kg preferred, and from about 0.025 mg P/kg to about 0.25 mg P/kg most
preferred; ABDP: from about 0.0025 mg P/kg to about 0.1 mg P/kg. with from about 0.0025
mg P/kg to about 0.04 mg P/kg preferred, and from about 0.0025 mg P/kg to about 0.025
mg P/kg most preferred; AHDP: from about 0.025 mg P/kg to about 1 mg P/kg, with from
about 0.025 mg P/kg to about 0.4 mg P/kg preferred, and from about 0.025 mg P/kg to
about 0.25 mg P/kg most preferred; pyr-EDP: from about 0.0025 mg P/kg to about 0.1
mg P/kg, with from about 0.0025 mg P/kg to about 0.04 mg P/kg preferred, and from
about 0.0025 mg P/kg to about 0.025 mg P/kg most preferred; pyr-EHDP: from about 0.00025
mg P/kg to about 0.01 mg P/kg, with from about 0.00025 mg P/kg to about 0.004 mg P/kg
preferred, and from about 0.00025 mg P/kg to about 0.0025 mg P/kg most preferred;
and HIP: from about 0.25 mg P/kg to about 10 mg P/kg, with from about 0.25 mg P/kg
to about 4 mg P/kg preferred, and from about 0.25 mg P/kg to about 2.5 mg P/kg most
preferred.
[0035] The preferred mode of administration for the polyphosphonates used in the present
invention is orally, but other modes of administration may be used including, without
limitation, intramuscular, intravenous, intraperitoneal, and subcutaneous administration,
as well as topical application. Adjustment of oral dosage levels to doses to be administered
other than orally is disclosed in the above cited patents and applications which have
been incorporated herein by reference. Adjustment of the above preferred oral doses
for dosing other than orally can easily be made by those skilled in the art. The daily
administration of the bone resorption inhibiting polyphosphonates may consist of one
dose every 24 hours, or several doses within the 24-hour period. Up to about 4 single
dosages per day may be administered.
[0036] The length of time during which the bone resorption inhibiting polyphosphonate is
administered is from about 1 day to about 90 days. It is preferred that EHDP-like
polyphosphonates be administered from about 1 to about 30 days, with about 7 to about
21 days most preferred. It is further preferred that CI2MDP-like polyphosphonates
be administered from about 30 to about 90 days, with about 80 to about 90 days preferred.
It is particularly preferred that EHDP-like polyphosphonates, especially EHDP, be
administered for 14 days, and followed by an 84 day rest period. Also particularly
preferred is that CI2MDP-like polyphosphonates, especially CI
2MDP, be administered for 84 days, and followed by an 84 day rest period.
[0037] When a relatively short period of time is used for dosing the bone resorption inhibiting
polyphosphonate (e.g., a 1 day dosing period), a relatively high dose (within the
above stated ranges) of the bone resorption inhibiting polyphosphonate is preferred.
Also for a relatively short period of dosing the polyphosphonate, It is preferred
that the method of administering the polyphosphonate be a more efficient method of
administration than oral administration, e.g., intravenous or subcutaneous.
[0038] By "rest period" as used herein is meant a period of time during which the patient
is not given a bone resorption inhibiting polyphosphonate, nor is the patient subjected
to a bone cell activating amount of a bone cell activating compound or other conditions
which would result in significant activation or inhibition of new bone remodeling
units ("BRU"; the packet of bone turnover in the adult skeleton) during this time.
It is this fact which further distinguishes the present invention from other regimens
of the art (see, e.g., Rasmussen et al., "Effect of Combined Therapy with Phosphonate
and Calcitonin on Bone Volume in Osteoporosis", Metabolic Bone Disease and Related
Research, 2, 107, (1980) and Anderson et al., Calcified Tissue International, 36,
341-343 (1984)), which require the use of a bone cell activating compound all the
time (e.g., Rassmussen et al.) or during part of the rest period (e.g., Anderson et
al.).
[0039] By "bone cell activating compound" as used herein is meant a compound which increases
the rate of activation of new BRU's. The concepts and terminology relating to bone
cell activation are described in more detail in Frost, Clinical Orthopedics and Related
Research, 143, 227-244 (1979); Rasmussen et al., Metabolic Bone Disease and Related
Research, 2, 107-111 (1980); Frost, Metabolic Bone Disease and Related Research, 4,
281-290 (1983); and Frost, Orthopedic Clinics of North America, 12, 692-737 (1981);
the disclosures of all of which are incorporated herein by reference. In most cases
this increased rate of activation is initially manifested by an increase in the number
of bone resorbing cells and bone resorbing sites. Biochemical indices of skeletal
remodeling, such as urinary hydroxyproline levels, are expected to become elevated
according to the magnitude of the response to the bone cell activating compound. Specific
examples of such compounds are parathyroid hormone (PTH), inorganic phosphate, growth
hormone, fluoride, thyroid hormones (e.g. thyroxine), certain vitamin D metabolites
and prostaglandins.
[0040] By "bone cell activating amount" as used herein is meant an amount of the bone cell
activating compound sufficient to effect a medically significant increase in the rate
of activation of new BRUs. Specific examples of bone cell activating compounds, and
their bone cell activating amounts, are: inorganic phosphate: above about 4 mg/kg/day
(P.O.) of phosphorous; 1,25-dihydroxy vitamin D
3 and other 1-hydroxy vitamin D metabolites: above about 0.001 microgram/kg/day (P.O.);
25-hydroxy vitamin D
3 and other 25-hydroxy vitamin D metabolites (not including 1,25-dihydroxy vitamin
D metabolites); above about 0.1 microgram/kg/ day (P.O.); inorganic fluoride (e.g.
sodium fluoride): above about 0.1 mg/kg/day F per day (P.O.); thyroxine: above about
0.01 mg/kg/day (P.O.); triiodothyroxine: above about 0.1 microgram/kg/day (P.O.);
prostaglandin PGE
2: above about 0.1 mg/kg/ day (P.O.); parathyroid hormone 1-34: above about 0.1 microgram/kg/day
(S.C.).
[0041] However, this is not to say that no chemicals may be administered to the patient
during the rest period. Nutrient supplements like calcium, vitamin D (to be distinguished
from bone cell activating amounts of bone cell activating metabolites of vitamin D)
iron, niacin, vitamin C and other vitamin or mineral supplements (which do not significantly
affect the BRUs) can beneficially be administered during the rest period. Certain
medications which do not significantly affect the BRUs, such as, for example, antibiotics
(e.g., penicillin), may also be administered during the rest period. However, medications
which significantly affect the BRUs, such as, e.g., calcitonin and adreno- corticosteroids,
are not to be administered during the rest period. A placebo (e.g. , a sugar pill)
may also be administered during the rest period to assist in following the regimen
of the present invention, especially if no daily supplement is being given during
the rest period and for use in a kit of the present invention.
[0042] While a rest period as short as about 30 days may be utilized, it is preferred for
the present invention that the rest period, for all polyphosphonates, be from about
50 days to about 120 days. More preferred, for all potyphosphonates, is a rest period
of from about 70 days to about 100 days, with about 84 days most preferred.
Thyroparathyroidectomized (TPTX) Rat Model
[0043] The polyphosphonates are evaluated for in vivo bone resorption inhibition potency
by an animal model system known as the thyroparathyroidectomized (TPTX) rat model.
The general principles of this model system are disclosed in Russell et al., Calcif.
Tissue Research, 6, 183-196 (1970), and In Muhlbauer and Fleisch, Mineral Electrolyte
Metab., 5, 296-303 (1981), the disclosures of which are incorporated herein by reference.
The basic biochemical concept of the TPTX system is inhibition of the parathyroid
hormone (PTH) - induced rise in serum and ionized calcium levels by the respective
bone active polyphosphonates.
Materials and Methods:
Materials
[0044] Low calcium and low phosphorous diets used were prepared by Teklad
R Test Diets (Harlan Industries, Madison, Wisconsin 53711; Order #TD82195) in a pellet
form of approximately 0.18% calcium and 0.22% phosphorous. The diets contained all
the essential vitamins and minerals required for the rat, with the exception of calcium
and phosphorous. The calcium and phosphorous levels of the pellets were verified analytically
(Procter ε Gamble Co., Miami Valley Laboratories, Cincinnati, Ohio).
[0045] PTH was acquired as a powdered bovine extract (Sigma Chemical Co., P.O. Box 14508,
St. Louis, Missouri, order #P-0892, Lot #72F-9650) at an activity of 138 USP units
per mg. PTH was prepared in 0.9% saline such that the final concentration was 100
U.S.P./ml. All solutions were filtered through a #4 Whatman Filter Paper and refiltered
through a 0.45 µm Metricel
R filter.
Dose SolUtions and Dosing Procedure
[0046] All solutions of compounds to be tested for bone resorption inhibition potency were
prepared for subcutaneous injection in 0.9% normal saline and adjusted to pH 7.4 using
NaOH and/or HCI. Dose solution calculation was made by considering the mass of powder
(based on molecular weight, hydration) of the active material in mg/kg (body weight)
that corresponds to mg P/kg. Concentrations were based on dosing 0.2 ml/100 grams
of body weight. Initially, all compounds were administered at 0.01, 0.1, 1.0, and
sometimes 10 mg P/kg/day for 4 days. Where necessary the test was repeated, whereby
the animals were administered with 0.5 X and 0.2 X LED in order to refine the determination
of LED. Adjustments in dosage based on changes in body weight were made on a daily
basis.
Animals
[0047] In this study 50 male Wistar rats weighing approximately 150-160 grams were thyroparathyroidectomized
surgically by the breeder (Charies River Breeding Laboratories). All rats were double
housed on arrival in suspended cages with Purina Laboratory Rodent Chow and tap water
ad libitum. After acclimation to the laboratory environment for 3-5 days, the rats
were placed on a low calcium, low phosphorous (0.18%/0.22%) diet (Teklad
R) and given 2% (W/V) calcium gluconate supplemented deionized water via water bottles.
Method
[0048] On day four of low-calcium diet all rats were anesthetized with Ketaset
R (Ketamine Hydrochloride, 100 mg/ml, Bristol Myers), 0.10 ml/100 grams of body weight,
weighed and then bled from the retro-orbital venous plexus for serum total calcium
analysis using Flame Atomic Absorption (FAA). All rats weighing less than 180 grams
were eliminated from the study. Animals were then randomized statistically such that
the mean total serum calcium for each group was the same. Only rats deemed hypo- calcemic
(total serum calcium ≤8.0 mg/dl) were placed in study groups comprising six animals
per group.
[0049] Treatments with the various compounds commenced on day 6 and lasted through day 9
of the study (at 1:00 P.M. each day). Dose solutions were prepared to be given at
constant rate of 0.2 ml/100 grams of body weight subcutaneously in the ventral skin
flap where the hind leg meets the torso. All rats were weighed and dosed daily. A
25 gauge 518" needle was used to administer drug, alternating dose sites daily. On
day 8, animals were changed to deionized, distilled water via water bottles. On day
9 all rats were fasted in the afternoon at approximately 4:00 P.M. On day 10 of study
no treatment was given. In the morning a 600 µl sample of whole blood was collected
from each rat in Microtalner (B-D#5060) serum separator tubes for serum total calcium
(FAA). Two 125 µl samples of heparinized whole blood were also collected to be used
for ionized calcium analysis. immediately following blood collection all rats were
weighed and injected with bovine parathyroid hormone subcutaneously at a rate of 75
USP (filtered) per 100 grams of body weight. Blood sampling for total and ionized
calcium was repeated three and one-half hours post-PTH injection.
[0050] All pre- and post-PTH total and ionized calciums were statistically analyzed for
significance compared to PTH alone (control) using Students t-test, analysis of variance,
and their non-parametric equivalents. The post minus pre-change and % change were
also determined on calcium levels and pre-drug vs post-drug body weights.
[0051] The physiological effect of the PTH challenge is a rise in serum calcium level, with
peak activity observed at three and one-half hours. Since the hormonal and dietary
controls of calcium metabolism are minimized in the TPTX model, an observed increase
in serum calcium level is presumably the result of resorption of bone material. Since
polyphosphonates tend to inhibit resorption of bone materials, the animals pretreated
with polyphosphonate showed a rise in serum calcium level after PTH challenge which
was less than that found in control animals which had been treated with saline vehicle
instead. The lowest dose at which the polyphosphonate is capable of inhibiting bone
resorption, as evidenced by a decreased rise in serum calcium upon PTH challenge,
is a measure of the bone resorption inhibition potency of the polyphosphonate. The
LED values of the bone resorption inhibition potency of representative bone resorption
inhibiting polyphosphonate compounds as determined by the TPTX rat model are presented
in Table I.

Schenk Model
[0052] The polyphosphonates are evaluated for in vivo bone resorption inhibition and mineralization
inhibition in an animal model system known in the field of bone metabolism as the
Schenk Model. The general principles of this model system are disclosed in Shinoda
et al., Calcif. Tissue Int., 35, 87-99 (1983); and in Schenk et al., Calcif. Tissue
Res. 11, 196-214 (1973), the disclosures of which are incorporated herein by reference.
Materials and Methods:
Animals
[0053] Preweaning 17-day-old (30 gms) male Sprague Dawley rats (Charles River Breeding Laboratories)
were shipped with their mothers and placed in plastic cages with their mothers upon
arrival. At 21 days of age, pups receiving Rat Chow and water ad libitum were randomly
allocated into treatment groups comprising five animals per group, except for control
animals receiving saline vehicle which had 10 rats per group. On day 0 and again on
day 1 all animals were given a subcutaneous injection of Calcein (Sigma) as a 1% solution
in 0.9% NaCl solution to label the skeleton.
Dose Solutions and Dosing Procedure
[0054] All solutions were prepared for subcutaneous injection in 0.9% normal saline and
adjusted to pH 7.4 using NaOH and/or HCl. Dose solution calculation was made by considering
the mass of powder (based on molecular weight, hydration) of the active material in
mg/kg (body weight) that corresponds to mg P/kg. Concentrations were based on dosing
0.2 mi/100 g body weight. Initially, all compounds were administered at 0.1, 1.0 and
10.0 mg P/kg/day for 7 days. Compounds showing activity at 0.1 mg P/kg/day were then
tested at logarithmic decrements down to 0.001 mg P/kg/day. Adjustments in dosage
based on changes in body weight were made on a daily basis.
Necropsy, Tissue Processing and Histomorphometry
[0055] On day 8 after the start of dosing, all animals were sacrificed by C0
2 asphyxiation. Tibias were dissected free and placed in 70% ethyl alcohol. One tibia
was dehydrated in graded ethanol solutions and embedded in methyl methacrylate using
a rapid procedure described in Boyce et al., Lab. Investig., 48, 683-689 (1983), the
disclosures of which are incorporated herein by reference. The tibia was sectioned
longitudinally through the metaphyseal area (Leitz saw microtome at 150µ) . Specimens
were stained on one surface with silver nitrate and mounted on microscope slides for
evaluation with a Quantimet Image Analyzer (Cambridge Instruments, Inc.) using both
incandescent and ultraviolet illumination. Metaphyseal trabecular bone content was
measured in the region between the fluorescent label and the growth plate: expressed
as percent of total area (bone + marrow). Epiphyseal growth plate width was obtained
as the mean value of 10 equally-spaced measurements across the section.
[0056] Statistical evaluation of data was made using parametric and non-parametric analysis
of variance and Wilcoxon's rank sum test to determine a statistically significant
effect compared to control animals.
[0057] The Schenk model provided data for In vivo bone resorption inhibition by the compounds.
The lowest effective (antiresorptive) dose ("LED") for representative compounds tested,
as determined by the Schenk model, are provided in Table II.

[0058] Diphosphonate compounds which have a bone mineralization inhibiting effect cause
widening of the epiphyseal growth plate, since matrix production continues but mineralization
is impeded. The widening of the epiphyseal growth plate as observed in the Schenk
model is, therefore, a measure of the mineralization inhibiting effect of the diphosphonate
compound tested.
[0059] The lowest tested dosages producing a statisticaily significant widening of epiphyseal
growth plate for compounds tested are given in Table III.

[0060] The present invention further relates to a kit for conveniently and effectively implementing
the method of treatment utilizing the cyclic regimen of the present invention. This
kit would be suited for use in a cyclic regimen for the treatment or prevention of
osteoporosis, in humans or lower animals afflicted with or at risk to osteoporosis,
said cyclic regimen comprising alternating for two or more cycles the administration
of a bone resorption inhibiting polyphosphonate and a rest period, said kit containing
the following components:
(a) from about 1 to about 90 daily doses, each dose containing a limited and effective
amount of a bone resorption inhibiting polyphosphonate, with from about 0.25 X LED
to about 4 X LED of polyphosphonate preferred, and from about 0.25 X LED to about
2.5 X LED of polyphosphonate most preferred; and
(b) from about 50 to about 120 daily doses, preferred being from about 70 to about
100 daily doses, with about 84 daily doses most preferred, of a placebo or a nutrient
supplement; and a means for having the components arranged in a way as to facilitate
compliance with the regimen. Preferred periods for administering the polyphosphonates,
preferred dosages, preferred cycle times, preferred rest periods, preferred polyphosphonates,
and other preferred values for use in a kit of the present invention are as described
more fully above for the method of treatment of the present invention.
[0061] Assuming that the majority of subjects afflicted with or at risk to osteoporosis
weigh between about 10 kg and 100 kg, the range of the daily safe and effective amount
of the preferred bone resorption inhibiting polyphosphonates for use in a kit of the
present invention are: EHDP: from about 2.5 mg P to about 400 mg P, with from about
2.5 mg P to about 250 mg P preferred; CI
2MDP: from about 1.2 mg P to about 500 mg P, with from about 1.2 mg P to about 200
mg P preferred, and with from about 1.2 mg P to about 125 mg P most preferred; APD:
from about 0.25 mg P to about 100 mg P, with from about 0.25 mg P to about 40 mg P
preferred, and from about 0.25 mg P to about 25 mg P most preferred; ABDP: from about
0.025 mg P to about 10 mg P, with from about 0.025 mg P to about 4 mg P preferred,
and from about 0.025 mg P to about 2.5 mg P most preferred; AHDP: from about 0.25
mg P to about 100 mg P, with from about 0.25 mg P to about 40 mg P preferred, and
from about 0.25 mg P to about 25 mg P most preferred; pyr-EDP: from about 0.025 mg
P to about 10 mg P, with from about 0.025 mg P to about 4 mg P preferred, and with
from about 0.025 mg P to about 2.5 mg P most preferred; pyr-EHDP: from about 0.0025
mg P to about 1.0 mg P, with from about 0.0025 mg P to about 0.4 mg P preferred, and
from about 0.0025 mg P to about 0.25 mg P most preferred; HIP: from about 2.5 mg P
to about 1000 mg P, with from about 2.5 mg P to about 4CO mg P preferred, and from
about 2.5 mg P to about 250 mg P most preferred.
[0062] Strict compliance with the above-described cyclic regimen is believed to be essential
for its success. The kit of the present invention is designed to facilitate such strict
compliance in that it provides a convenient and effective means for assuring that
the patient takes the appropriate medication in the correct dosage on each day of
the regimen.
[0063] In one specific embodiment of the invention raid means is a card having arranged
thereupon the components of the treatment regimen in the order of their intended use.
An example of such a card is a so-called blister pack. Blister packs are well-known
in the packaging industry, and are being widely used for the packaging of pharmaceutical
unit dosage forms (tablets, capsules, and the like). Blister packs generally comprise
a sheet of relatively stiff material, covered with a foil of a, preferably transparent,
plastic material. During the packaging process, recesses are formed in the plastic
foil. The recesses have the size and shape of the tablets or capsules to be packed.
Next, the tablets or capsules are placed in the recesses, and the sheet of relatively
stiff material is sealed against the plastic foil at the face of the foil which is
opposite from the direction in which the recesses are formed. As a result, the tablets
or capsules are sealed in the recesses, between the plastic foil and the sheet. Preferably,
the strength of the sheet is such that the tablets or capsules can be removed from
the blister pack by manually applying pressure on the recesses whereby an opening
is formed in the sheet at the place of the recess. The tablet or capsule can then
be removed via said opening.
[0064] It is desirable to provide a memory aid on the card, e.g. in the form of numbers
next to the tablets or capsules, whereby the numbers correspond with the days of the
regimen which the tablets or capsules so specified should be ingested. Another example
of such a memory aid is a calendar printed on the card, e.g. as follows "First Week,
Monday, Tuesday, ..., etc. Second Week, Monday, Tuesday, ...", etc. Other variations
of memory aids will be readily apparent. A "daily dose" can be a single tablet or
capsule or several pills or capsules to be taken on a given day. The memory aid should
reflect this.
[0065] The term "card", as used herein, is not limited to a flat, sheet-like structure.
The term includes structures as described above which are folded so as to reduce their
planar dimensions; the term further includes a plurality of cards which, combined,
contain the components for the treatment regimen. An example of the latter would be
a stack of cards, marked "Week 1", "Week 2". etc., each containing the components
of the regimen for one week of treatment. The tablets or capsules may also be arranged
on a narrow strip, one after the other; the material of the strip is preferably flexible,
so that it can be wound on a reel. The strip may be perforated so that dally doses
can be torn off.
[0066] In another specific embodiment of the invention said means is a dispenser designed
to dispense said daily doses, one at a time, in the order of their intended use. Preferably,
the dispenser is equipped with a memory-aid, so as to further facilitate compliance
with the regimen. An example of such a memory-aid is a mechanical counter which indicates
the number of dally doses that has been dispensed. Another example of such a memory-aid
is a battery-powered micro-chip memory coupled with a liquid crystal readout, or audible
reminder signal which, for example, reads out the date that the last daily dose has
been taken and/or reminds one when the next dose is to be taken.
[0067] Single-unit dispensers are well-known and are being widely used in, e.g., vending
machines. The concepts of such machines are directly suitable for, or easily adaptable
to, use in the dispensers of this embodiment of the present invention.
[0068] Specific examples of the method of treatment of the present invention, and of kits
for assuring the necessary strict compliance with the regimen according to the method
of treatment of the present invention, are:
Example I
[0069] Patients clinically diagnosed as suffering from osteoporosis are subjected to a treatment
regimen according to the present invention as follows.
[0070] Each patient is subjected to from 3 to 8 cycles, each cycle consisting of (a) a period
of 14 days during which the patients receive 5 mg/kg/day of DIDRONEL (Norwich Eaton
Pharmaceuticals, Norwich, NY); and (b) a rest period of 84 days during which the patients
receive a diet which is verified to contain a minimum of 1 g/day of calcium.
[0071] The treatment regimen results in a significant alleviation of osteoporotic conditions.
The use of the
?bove regimen by patients at risk to osteoporosis, for example postmenopausal women,
has a prophylactic effect against the onset of osteoporosis in the patients.
[0072] A kit for use in a regimen for treatment or prevention of osteoporosis, as described
above, Is made up as follows:
Three slip cases, each case being 4-3/4 in. wide x 8-1/2 In. high x 6 in. deep (about
12 cm x 21-1/2 cm x 15 cm) and containing 13 cards (blister packs) of 4-3/4 in. x
8-1/2 in. (about 12 cm x 21-1/2 cm), are boxed side by side in a box 8-1/2 in, wide
x 6 in. high x 14-1/4 in, deep (about 21-1/2 cm x 15 cm x 36 cm). The box opens on
the 8-1/2 in, x 6 In. side (about 21-1/2 cm x 15 cm) to allow the first slip case,
which contains the first cycle's doses, to be removed. The second and third slip cases
cannot be removed from the box until the preceding case has been removed. The first
card in this slip case contains 14 tablets, each tablet containing 400 mg DIDRONEL
(Norwich Eaton Pharmaceuticals, Norwich. NY). The tablets are arranged in 4 rows of
3 tablets per row, and a 5th row with 2 tablets in the row. Printed on the card, next
to each tablet, are the words "Day 1", "Day 2", ... etc. through "Day 14".
[0073] The remaining 12 cards each contain 14 capsules, each capsule containing 500 mg of
calcium. Printed on each card are rectangular boxes, such that each box contains two
capsules (i.e., 7 boxes per card; one daily dose is two capsules, each capsule containing
500 mg of calcium for a total daily dose of 1 g of calcium). The boxes are marked
"Day 15". "Day 16", ... etc. through "Day 98" on the last card.
[0074] After all the doses which are contained in the first slip case have been taken (i.e.,
after day 98), the second slip case (i.e., cycle two of the treatment regimen) is
removed from the box. This slip case contains 13 cards containing tablets arranged
as in the first slip case, except the days noted on the cards correspond to the day
of the treatment for the second cycle. Thus, the DIDRONEL tablets are marked as "Day
99" through "Day 112", and the calcium tablets to be taken during the rest period
are marked as "Day 113" through "Day 196". The third slip case, which is removed last
from the box after day 196, is similarly organized for days 197 through 294. The last
card of this third slip case may contain a printed reminder that a renewal prescription
should be obtained.
Example II
[0075] Patients clinically diagnosed as suffering from osteoporosis are subjected to a treatment
regimen according to the present invention as follows. Each patient is subjected to
from 3 to 8 cycles, each cycle consisting of (a) a period of 84 days during which
the patients receive 20 mg/kg/day of disodium C1
2MDP and (b) a rest period of 84 days during which the patients receive a diet which
is verified to contain a minimum of 1 g/day of calcium.
[0076] The treatment regimen results in a significant alleviation of osteoporotic conditions.
The use of the above regimen by patients at risk to osteoporosis, for example postmenopausal
women, has a prophylactic effect against the onset of osteoporosis in the patients.
[0077] A kit for use in a regimen for treatment or prevention of osteoporosis, as described
above, is made as indicated in Example 1, with this kit having tablets totaling 1400
mg/day of disodium Cl
2MDP and the number of cards increased and labeled to accommodate 84 days of dosing
with disodium Cl
2MDP per slip case (i.e., per cycle).
[0078] The treatment regimen is varied, for example, as indicated in Table IV.

[0079] A treatment regimen consisting of the above cycles results in an appreciable alleviation
of osteoporotic conditions in patients clinically diagnosed as suffering from osteoporosis.
Also, in patients at risk to osteoporosis, a treatment regimen consisting of the above
cycles has a prophylactic effect against the onset of osteoporosis in these patients.
Example III
[0080] Postmenopausal osteoporotic females with spinal compression fractures are subjected
to a treatment regimen according to the present invention as follows.
[0081] Each patient is subjected to three cycles which utilize about 20 mg/kg/day of disodium
Cl
2MDP according to the following regimen: 28 days of daily dosing with disodium Cl
2MDP, followed by an 84 day rest period, followed by 84 days of daily dosing with disodium
Cl
2MDP, followed by an 84 day rest period, followed by 28 days of daily dosing with disodium
C12MDP. This regimen results in a substantial increase in total bone mass in patients
receiving treatment according to the regimen of the present invention.